1. Field of the Invention
The invention concerns a Marx generator and more specifically to Marx generators capable of storing and delivering energies of the order of 100 kJ to several megajoules.
2. Description of Related Art
A Marx generator is a high voltage pulse generator whose essential function is to store electrical energy and then to deliver it as a high power, high voltage pulse. It consists essentially of a series of capacitors connected together in such a way that they can be charged in parallel and discharged in series. A power supply circuit provides the parallel charge to the capacitors which, being connected in series through spark gaps, discharge in series when the spark gaps are actuated.
The capacitors discharge into a load connected across the two output terminals of the generator.
A Marx generator is essentially characterized by three electrical parameters:
the energy W it is capable of storing; PA1 its output voltage V.sub.s, i.e. the maximum peak voltage of the output pulse it can deliver; and PA1 the rise time of this pulse, which is equivalent to one quarter of the period of the Marx generator oscillating independently when its output terminals are short-circuited. This quarter period is expressed as follows: ##EQU1## where L is the total inductance of the generator. PA1 either to increase the voltage V.sub.s, or PA1 to reduce the inductance L of the system.
This expression sets out an important and general law governing the behavior of this type of electrical system: in order to build Marx generators with minimum quarter period for a given stored energy, it is necessary:
A review of the characteristics of a few existing Marx generators shows that the fundamental disadvantage of existing systems lies in that energy pulses with a short rise time can be obtained only by means of a high voltage V.sub.s (in practice, above 700 kV). In certain cases, this high voltage requirement is justified only by a demand for speed and penalizes the performance of systems using these Marx generators by imposing greater spacing between the different conductors and a substantial increase in the quality of dielectrics used. Moreover, increasing the operating voltage of a Marx generator inevitably produces an increase in its inductance by imposing greater spacing between the conductors. Finally, the costs of maintaining such systems increased significantly with their operating voltages.